1. Field of the Invention
This invention relates to an automotive internal combustion engine having a cylinder block which is not provided with a so-called upper block deck, and more particularly to an engine construction made of a light alloy and produced by die-casting and having a firm connection between a cylinder head and the cylinder block.
2. Description of the Prior Art
In connection with automotive internal combustion engines, it is well known to die cast a cylinder block using light alloy as the material thereof. Such a die-casted cylinder block is in general not provided with a so-called upper block deck, so that the upper part of a water jacket wall of the cylinder block is separate from the upper part of a cylinder row structure including a plurality of cylinder sections each being formed therein with an engine cylinder bore. A cylinder block produced by conventional casting using molding sand is provided with an upper block deck which serves to integrally connect the water jacket wall upper part and the cylinder row structure upper part. The reason why the upper block deck is not provided in the die-casted cylinder block is that a metallic die for the water jacket is drawn out upwardly during die-casting thereof. As a result, the upper part of the water jacket wall is not restrained at all by each cylinder section. This leads to shortage in flexural and torsional rigidities of the cylinder block, and, particularly the upper part of the cylinder block is susceptible to noticeable vibrations.